manimの作法 その56

#概要

manimの作法、調べてみた。
AnimatedStreamLines、使ってみた。

#サンプルコード

from manimlib.imports import *

def joukowsky_map(z):
	if z == 0:
		return 0
	return z + fdiv(1, z)

def derivative(func, dt = 1e-7):
	return lambda z: (func(z + dt) - func(z)) / dt

def cylinder_flow_vector_field(point, R = 1, U = 1):
	z = R3_to_complex(point)
	return complex_to_R3(derivative(joukowsky_map)(z).conjugate())

class test(Scene):
	def construct(self):
		self.add_vector_field()
		self.begin_flow()
		self.add_circle()
		self.wait(5)
	def add_vector_field(self):
		vector_field = VectorField(cylinder_flow_vector_field, )
		for vector in vector_field:
			if get_norm(vector.get_start()) < 1:
				vector_field.remove(vector)
		vector_field.set_fill(opacity = 0.75)
		self.modify_vector_field(vector_field)
		self.add_foreground_mobjects(vector_field)
	def begin_flow(self):
		stream_lines = StreamLines(cylinder_flow_vector_field, colors = [BLUE_E, BLUE_D, BLUE_C], start_points_generator_config = {
			#	"delta_x": 0.125,
			#	"delta_y": 0.125,
		}, virtual_time = 5, )
		self.add(stream_lines)
		for stream_line in stream_lines:
			if get_norm(stream_line.points[0]) < 1:
				stream_lines.remove(stream_line)
		self.modify_flow(stream_lines)
		stream_line_animation = AnimatedStreamLines(stream_lines)
		stream_line_animation.update(3)
		self.add(stream_line_animation)
	def add_circle(self):
		circle = Circle(radius = 1, stroke_color = YELLOW, fill_color = BLACK, fill_opacity = 1, )
		self.modify_flow(circle)
		self.add_foreground_mobjects(circle)
	def modify_flow(self, mobject):
		pass
	def modify_vector_field(self, vector_field):
		pass

#生成した動画

以上。